The face of the ancient human known as the 'Denisovans,' which remained a mystery in human evolution for 17 years after being first excavated in 2008, has finally been revealed. The skull of the hominin discovered in Harbin, northeastern China, has been confirmed to be Denisovan.
Researchers from the Chinese Academy of Sciences and Hebei Geological University reported on the 19th that they confirmed through analysis of the skull's proteins and DNA that the Harbin skull belonged to a Denisovan who lived at least 146,000 years ago. Until now, traces of Denisovans were limited to bone fragments and teeth. The research findings were published that day in the international journals 'Science' and 'Cell.'
Before Homo sapiens, the direct ancestors of modern humans migrated to Eurasia, there were earlier human populations. These included the Neanderthals and Denisovans, who were cousins of the extinct humans.
Neanderthals left Africa and settled in Eurasia around 400,000 years ago. The Denisovans, named after the cave in Siberia where their finger bone and molar were first discovered in 2008, are believed to have separated from Neanderthals 350,000 years ago and spread into Asia.
The skull analyzed by the researchers was discovered in 2021. At that time, experts speculated that the skull belonged to a Denisovan due to its large and thick eyelid area and large upper jaw, but they could not secure genetic evidence because they were unable to extract enough DNA from the bones and teeth.
Instead of searching for DNA in the skull itself, the researchers successfully extracted DNA from 0.3 mg of tartar collected from a molar. Tartar is a substance that solidifies on teeth, and although it is less in quantity than bone or teeth, it still contains DNA. Notably, it is as hard as stone, which allows the DNA within it to be preserved stably over long periods.
The researchers found that the DNA extracted from the Harbin skull's tartar matched genetically with the mitochondrial DNA of existing Denisovan bones and teeth. This scientifically confirmed that the Harbin skull is indeed Denisovan.
Mitochondria, the energy-generating organelles located outside the cell nucleus, possess their own DNA. Mitochondria are primarily used to trace maternal genetic inheritance because they are passed down through the egg.
In addition to the tartar DNA, the researchers analyzed 95 proteins extracted from the skull. As a result, they identified three unique variations, including a protein variation distinctive to Denisovans found in Tibet and Taiwan. These were different from modern humans and Neanderthals.
The Harbin skull analyzed this time is remarkably well-preserved, opening up new possibilities for more specifically reconstructing the appearance of Denisovans, which had only been known through fragmented fossils. Until now, Denisovans were known only from fossil fragments such as fingers, jawbones, and teeth, and little was understood about what they actually looked like.
The researchers noted, "This study does not merely reveal the identity of the Harbin skull; it also presents a new possibility that hominin fossils found in places like the Dali and Jinnyushan in China could belong to the Denisovan lineage."
References
Science (2025), DOI: https://doi.org/10.1126/science.adu9677
Cell (2025), DOI: https://doi.org/10.1016/j.cell.2025.05.040